The term extinction threshold refers to a critical value of some attribute, such as the amount of habitat in the landscape, below which a population, a metapopulation, or a species does not persist. In this paper we discuss the existence and behavior of extinction thresholds in the context of metapopulation models. We review and extend recent developments in the theory and application of patch ...

Many hypotheses have been proposed to explain multiple mating in females. One of them is bet hedging, that is avoiding having no or very few offspring in any given generation, rather than maximizing the expected number of offspring. However, within-generation bet hedging is generally believed to be an unimportant evolutionary force, except in very small populations. In this study, we derive pre...

Background & Aim: German chamomile is one of the most important medicinal plants. So, assessment of genetic diversity and relationship among the traits are very essential in chamomile breeding programs. Determination of the best indirect selection criteria for genetic improvement of essence percent and dry flower yield of German chamomile (Matricaria chamomilla L.) populations...

The Kean–Barlow model predicts how the equilibrium distribution and abundance of a population may be affected by local rates of increase, dispersal, colonisation, and extinction. Here, the model is parameterised for three insects: the Glanville fritillary Melitaea cinxia in Åland, Finland, the ribbonwood aphid Paradoxaphis plagianthi in Christchurch, New Zealand, and the coxella weevil Hadramph...

Climate change is known to shift species' geographical ranges, phenologies and abundances, but less is known about other population dynamic consequences. Here, we analyse spatio-temporal dynamics of the Glanville fritillary butterfly (Melitaea cinxia) in a network of 4000 dry meadows during 21 years. The results demonstrate two strong, related patterns: the amplitude of year-to-year fluctuation...

abstract genetic diversity of german chamomile (matricaria chamomilla l.) populations in iran was evaluated using morphological, agronomical and phonological characteristics and compared with three cultivars from germany, hungary and iran. in this experiment, statistical design of rcbd with three replications was used, sixteen quantitative traits were measured such as yield, flower number per p...

An alternative means by which to examine the importance of assimilates supply to flower and pod formation is to analyze the relationships of leaf area index (LAI), above-ground dry matter (ADM), leaf area duration (LAD) and crop growth rate (CGR) around flowering with flower number and pod/flower ratio. For this objective, an experiment was conducted at Agricultural Research Station of Gonbad, ...